Display devices that conform to the Video Electronics Standard Association (VESA) standard contain a parameter block (known as the Extended Display Identification Data, or EDID) that specifies the various resolutions and timing modes that the display supports. This parameter block is read via an Inter-Integrated Circuit (I2C) connection between the video card and the monitor using a protocol known as the Data Display Channel (DDC).
FIG. 1 illustrates a typical computer monitor system in accordance with the prior art. The system comprises a computer 101 and display monitor 102. The computer 101 may be a desktop or notebook device, as well as any computing device that is capable of sending video data to an external display device. The computer 101 and display monitor 102 are connected by a wired link that includes a bidirectional I2C connection 110 and a unidirectional video connection 120.
Before sending video data to the display monitor, the computer needs to know the display's parameters contained in the EDID. In a typical VESA system, such as depicted in FIG. 1, the 2-wire I2C connection on the cable (be it VGA, DVI, etc.) is used to communicate EDID information. The host computer 101 acts as the I2C master, requesting blocks of the EDID from the monitor 102, which acts as the slave. The computer 101 acquires the needed video parameters by sending an EDID request 130 to the display monitor 102, which in turn sends the EDID information 140 to the computer.
With the introduction of wireless video transmission, the wired connection between the computer and the display is replaced by wireless adapters. In such a configuration, it is important that any wireless video system pass the EDID information about the target monitor to the host driving the wireless video source adapter on the computer. This allows the host to fine tune the video card's signal (which is duplicated on a wireless video sink adapter at the monitor) to match the idiosyncrasies of the target monitor. Further complicating the problem is the fact that most operating systems, and in particular Windows, do not provide any way to inject monitor information into the system other than the standard method of fetching it directly from the monitor via I2C.
Therefore, a need exists for efficiently obtaining display monitor EDID information in a wireless computer video system.